Question

我有一些代码合并了两个文本文件（第一个和第二个）。如何检查第一个文件的内容是否在第二个文件内并跳过合并？

[Code]
procedure AppendFile(const SrcFile, DestFile: string);
var
  SrcStream: TFileStream;
  DestStream: TFileStream;
begin
  SrcStream := TFileStream.Create(SrcFile, fmOpenRead);
  try
    DestStream := TFileStream.Create(DestFile, fmOpenWrite);
    try
      DestStream.Seek(0, soFromEnd);
      DestStream.CopyFrom(SrcStream, SrcStream.Size);
    finally
      DestStream.Free;
    end;
  finally
    SrcStream.Free;
  end;
end;

Answer 1

最简单的Unicode安全实现是使用TStringList class：

function NeedAppend(const SrcFile, DestFile: string): Boolean;
var
  SrcContents: TStringList;
  DestContents: TStringList;
begin
  SrcContents := TStringList.Create();
  DestContents := TStringList.Create();
  try
    SrcContents.LoadFromFile(SrcFile);
    DestContents.LoadFromFile(DestFile);

    Result := (Pos(SrcContents.Text, DestContents.Text) = 0);
  finally
    SrcContents.Free;
    DestContents.Free;
  end;

  if not Result then
  begin
    Log('Contents present already, will not append');
  end
    else
  begin
    Log('Contents not present, will append');
  end;
end;

虽然效率不高，但文件很大。

一旦你以这种方式实现了差异，你可以将它与合并这个简单的代码结合起来：

procedure AppendFileIfNeeded(const SrcFile, DestFile: string);
var
  SrcContents: TStringList;
  DestContents: TStringList;
begin
  SrcContents := TStringList.Create();
  DestContents := TStringList.Create();
  try
    SrcContents.LoadFromFile(SrcFile);
    DestContents.LoadFromFile(DestFile);

    if Pos(SrcContents.Text, DestContents.Text) > 0 then
    begin
      Log('Contents present already, will not append');
    end
      else
    begin
      Log('Contents not present, will append');

      DestContents.AddStrings(SrcContents);
      DestContents.SaveToFile(DestFile);
    end;
  finally
    SrcContents.Free;
    DestContents.Free;
  end;
end;

Inno Setup：比较两个文件的内容

1 个答案: